1. Field of the Invention
The present invention relates to an image processing system and a method for securely outputting image data.
2. Description of the Related Art
When image data such as scanned image data is uploaded from a network scanner or a multifunction peripheral (MFP) to an insecure file server for subsequent printing, the file contents are at risk of being viewed by unauthorized third parties. Japanese Patent Laid-Open No. 08-023442) discloses a known method for securing scanned image data by encryption prior to upload.
However, the disadvantage of encrypting the scanned image data prior to upload, is that the decryption key corresponding to the scanned image data cannot be securely obtained. It is assumed that the scanned image data is encrypted with the encryption key and the encrypted scanned image data is decrypted with the same encryption key.
The encryption key cannot be attached to the scanned image data, since it may become exposed to the public. Even if the encrypted scanned image data is decrypted with a decrypted key, the decrypted key cannot be attached to the scanned image data for the same reason. One method for avoiding public exposure is for the scanner and printer to share the same encryption key. However, the security level is set low since all jobs share the same encryption key.
Another method for improving security is to create different encryption keys for each job. In this method, the scanner displays a password to a user at encryption time such that the user can enter the password during printing. In another method, a printer creates and sends an encryption key to a scanner such that scanned image data is decrypted with the encryption key. Further yet, another method is provided in which a server creates and maintains encryption keys that can be shared by a scanner and a printer.
However, conventional methods have a number of disadvantages. In the case of password-protected systems, when a scanner displays the password, the user is required to remember the password. Similarly, the method where a printer creates and sends an encryption key is effective only when a printer to be used for printing is predetermined. Other printers cannot be employed and the user is required to remember which printers can be used. In the case where a server is provided, the server is likely to become a target for hacking, additional costs for installation and maintenance are required, and its address must be predetermined.